There is great interest in the generation of images using thermal transfer technology, particularly in the generation of images via near-infrared laser devices. In general, most of these systems rely on the conversion of light to heat energy by an IR absorber, and the subsequent transfer of colorant or other imaging material from the exposed areas to a receiver. The images derived may be monochrome, or by repetition of the process with various colored donors, a multi-colored image can be produced on a common receiver, useful for generating color proofs. The process can also be used to transfer other materials to a receiver, such as IR absorbing materials, UV absorbing materials, polymeric binders or other useful imaging materials. This process is described, for example, in U.S. Pat. No. 5,126,760 which discloses the use of an IR absorber to effect sublimation or diffusion of a colorant from a donor element to a receiver layer.
U.S. Pat. No. 5,278,023 discloses a propellant-containing thermal transfer donor element which is used to mass transfer colorants to a receiver element. However, there is a problem with this element in that during laser imaging, a portion of the infrared-absorbing material transfers to the receiving element and causes color contamination.
U.S. Pat. No. 5,171,650 a discloses a laser thermal donor element which uses ablation transfer mechanism to transfer a colorant to a receiver element. However, again there is a problem with this element in that during laser imaging, a portion of the infrared-absorbing material transfers to the receiving element and causes color contamination.
It is an object of this invention is to provide a laser donor element that is capable of transferring images without color contamination by other components contained within the donor element.
It is another object of this invention is to provide a rapid and efficient process for the transfer of a white pigment to a receiver which has improved whiteness.